Least Squares Full Wavefield Migration for Marine Seismic Imaging
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Solution Overview
Problem
Current marine seismic imaging methods often suffer from crosstalk artifacts when incorporating multiples, leading to incomplete and noisy seismic images, as they fail to effectively balance the contributions of primary and multiple wavefields, resulting in uneven illumination and limited subsurface coverage.
Innovation Solution
The proposed solution involves a least squares full wavefield migration method that directly computes earth reflectivity by treating marine survey receivers as virtual sources, expanding surface coverage and enhancing subsurface illumination, thereby reducing the need for high-density surveys and eliminating crosstalk artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If current marine seismic imaging methods incorporate multiples, then subsurface coverage is expanded, but crosstalk artifacts and noise increase
Solution Approach 1:
The patent converts the harmful crosstalk artifacts generated by multiple wavefields into beneficial information by using least squares full wavefield migration to properly image both primaries and multiples. This approach transforms the previously harmful interference patterns into useful subsurface reflections, eliminating artifacts while maintaining expanded subsurface coverage.
Solution Approach 2:
The patent changes the imaging parameters by using least squares full wavefield migration instead of conventional migration methods. This parameter change allows for proper balancing of primary and multiple wavefield contributions, resulting in artifact-free images with comprehensive subsurface coverage.
2Ease of manufacture
If conventional methods are used to image primaries and multiples, then processing is simpler, but illumination becomes uneven
Solution Approach 1:
The patent implements feedback through the least squares inversion process, which iteratively adjusts the imaging solution to balance the contributions of primary and multiple wavefields. This feedback mechanism ensures uniform subsurface illumination by continuously optimizing the weighting of different wavefield components during the imaging process.
3Measurement precision
If high-density surveys are conducted to improve image quality, then measurement precision increases, but survey cost and complexity increase
Solution Approach 1:
The patent converts the previously discarded multiple wavefields into useful imaging information, thereby achieving high measurement precision without requiring high-density surveys. By properly imaging multiples alongside primaries, the method extracts additional subsurface information from existing survey data, eliminating the need for increased survey density.
Solution Approach 2:
The patent makes the seismic imaging process multi-functional by simultaneously imaging both primary and multiple wavefields using the same survey data. This universal approach maximizes the information content of existing surveys, achieving high image quality without requiring separate high-density survey campaigns.
Data Source
AI summary
Inversion for marine seismic imaging of a full reflected wavefield can include generating an image of a subsurface formation by full wavefield migrating a recorded seismic wavefield and generating numerically modeled data using the image. A mismatch between the numerically modeled data and the seismic wavefield can be determined. Responsive to determining that the mismatch exceeds an inversion match threshold, the image can be updated using the mismatch between the numerically modeled data and the seismic wavefield.